On Monday 25 August 2008, Arnd Bergmann wrote:> On Monday 25 August 2008, Paul Mackerras wrote:> > > > > Since rc4 is out now, I understand if you feel more comfortable with> > > putting the patch into -next instead of -merge.> > > > Linus has been getting stricter about only putting in fixes for> > regressions and serious bugs (see his recent email to Dave Airlie on> > LKML for instance). I assume that the corruption is just in the data> > that is supplied to userspace and doesn't extend to any kernel data> > structures.> > That's right, please queue it for -next then.

I just realized that this patch never made it into powerpc-next afterall, neither benh nor paulus version. Whoever is handling it today,could you please pull

master.kernel.org:/pub/scm/linux/kernel/git/arnd/cell-2.6.git merge

to get this commit below. I have rebased it on top of the currentbenh/powerpc/next branch.

The issue is the SPU code is not holding the kernel mutex lock while adding samples to the kernel buffer.

This patch creates per SPU buffers to hold the data. Data is added to the buffers from in interrupt context. The data is periodically pushed to the kernel buffer via a new Oprofile function oprofile_put_buff(). The oprofile_put_buff() function is called via a work queue enabling the funtion to acquire the mutex lock.

The existing user controls for adjusting the per CPU buffer size is used to control the size of the per SPU buffers. Similarly, overflows of the SPU buffers are reported by incrementing the per CPU buffer stats. This eliminates the need to have architecture specific controls for the per SPU buffers which is not acceptable to the OProfile user tool maintainer.

The export of the oprofile add_event_entry() is removed as it is no longer needed given this patch.

Note, this patch has not addressed the issue of indexing arrays by the spu number. This still needs to be fixed as the spu numbering is not guarenteed to be 0 to max_num_spus-1.